William h



W. H. A. DA SON. VENTILA R.

Patented Jan. 10, 1893 NITED TATES ATENT FFICE.

WILLIAM H. A. DAVIDSON, OF BOSTON, MASSACHUSETTS, ASSIGNOR, BY DIRECTAND MESNE ASSIGNMENTS, TO THE DAVIDSON VENTILATIN G FAN COMPANY, OF SAMEPLACE.

VENTILATOR.

SPECIFICATION forming part of Letters Patent N 0. 489,466, dated January10, 1893.

Application filed June 9, 1891. Serial No. 395,629. (ModeL) To all whomit may concern.-

Be it known that I, WILLIAM H. A. DAVID- SON, of Boston, in the countyof Suffolk and State of Massachusetts, have invented certain new anduseful Improvements in Ventilators; and I do hereby declare thefollowing to be a full, clear, and exact description of theinvention,such as will enable others skilled in the art to which it appertains tomake and use the same.

My invention relates to an improvement in ventilating fans, the objectbeing to provide a fan which will be as light as possible and easyrunning and one which will accomplish with few parts what heretofore hasrequired more parts and greater complexity in construction.

A further object is to create a partial vacuum in the rear of the fanand in advance of the incoming and advancing current or column of air.

A further object is to make as compact a fan or wheel as possible and toincrease the velocity and the volume at the same time and to deliver thecurrents in such a manner as to meet with a minimum resistance from theatmosphere at the discharge face of the fan or wheel.

A further object is to providea fan of such construction that acomparatively large volume of air will be displaced with the expenditureof a minimum of power,and still further objects are to prevent deadcenters, lessen friction, prevent as far as possible the obstruction oflight and finally to so construct a fan that the first and greatestdraft in cutting the air will be close to the axle.

With these several objects in view my invention consists in certainnovel featuresof construction and combinations of parts as will behereinafter described and pointed out in the claims.

In the accompanying drawings, Figure 1 is a view in front elevation.Fig. 2 is. a rear View. Fig. 2 is a view in side elevation. Fig. 3 is adetached View of the preferred form of blade or templet. Fig. 4 is aview of a modification. Fig. 4c is a view of the form of blade employedin this modified form of fan. Fig. 5 is a view showing the faninountedin a blower case, and Fig. 6 is a sectional view showing ablower case provided with two fans.

The templet or blade required to produce the best results and subservemy objects is preferably shaped substantially as shown in Figs. 3 and 4.The blank shown in Fig. 3 is adapted to be bent along the dotted lineuntil the edge B-A is in the same line and plane with the edge G-F. Whenthus bent the blade or templet is in shape for attachment to the otherparts of the fan. It is secured at point F to the hub K and is setdiagonally thereto. by a brace L. At the outer edge BA it is secured toa peripheral ring. Different numbers of these blades may be employedjust so they do not overlap one another. It will be observed from theforegoing and from the drawings that a blade constructed after thisfashion has a scoop shape and being set diagonally at the hub, therounded edge is the first to enter the air, it being in advance of therest of the blade inthe rotation of the wheel or fan. Thus the firstcontact or cut is at a point near the hub where the greatest power lies.The blade bent as set forth presents a convex and concave surface oneach side, and in consequence after the air is once cut it glances offdiagonally and from the rapid rotation of the wheel is caught by theangle formed by the central crease in the blade, and discharged rearwardin lines approximately parallel with the axle of the fan or wheel. Itwill be further observed that the blades are so placed relative to oneanother that they at no point overlap and hence as the fan or wheelrotates the light is not obstructed, neither does one blade take the airor a portion of it from another.

The fan or wheel is strengthened by means of spokes S and the shaftingis revolublysupported in asuitable frame as shown.

In the form of blade or templet shown in Fig. 4 the bend extends frompoint C to the edge at point D. In this construction the braces L aredispensed with, one entire edge of the blade or templet being secured tothe hub. In this construction as well as in the former construction theair is first cut by the edges E of the blades and on account of the Itis also secured to the hub gradual inclining or sloping of the blades itis deflected forward through the fan on an incline at first and untilagain deflected by the portions H of the blades striking and pushing itforward and the outer portion of surface G abutting against it whichtogether resultsin turning the air from an oblique or diagonal course toa straight course or in lines parallel with the axle. The constructionthus combines in a single set of blades the pulling and pushing of theair which hitherto it has been considered necessary to employ two setsof blades to accomplish.

In the modification shown in Fig. 5 my fan is shown in a blower case forthe purpose of giving pressure to the air as well as agitating it andstarting it in circulation. In this construction it will be noticed thatthe air opening is equal in diameter to the diameter of the fan,thisbeing rendered possible from the fact that there is no back pressure ofair. The result is that the fan is driven with less than the usualamount of power and more air is agitated and it is discharged with equalpressure.

In the modification shown in Fig. 6 two fans are employed and the air istaken in on both sides of the case instead of one side only. It isdischarged in the usual way.

It is evident that slight changes might be resorted to in the form andarrangement of the several parts described without departing from thespirit and scope of my invention and hence I do not wish to limit myselfto the ex- 5 act construction herein set forth, but,

Having fully described my invention what I claim as new and desire tosecure by Letters- Patent, is:

1. In a ventilating fan or wheel, a blank bent diagonally into twoplanes, and bounded on two edges with converging curved lines, the othertwo edges bounded by converging substantially straight lines,substantially as set forth.

2. In a ventilating fan or wheel, the combination with a hub andperipheral ring, of blades bent diagonally into two planes and havingtwo converging curved edges and two converging substantially straightedges, the straight edges secured to the hub and ring, the attachment atthe ring being in rear of that at the hub.

3. A ventilating fan or wheel composed of a series of blades each bentdiagonally into two planes, two edges converging on curved lines and twoin substantially straight lines, substantially as set forth.

4. In a ventilating fan or wheel the combination with a hub and ring, ofblades composed of blanks of sheet metal bent diagonally into twoleaves, one edge of each blade secured to the ring and one edgeextending from the ring more or less directly to the hub, said edgesbeing in the same plane with the ring, substantially as set forth.

In testimony whereof I have signed this specification in the presence oftwo subscribing witnesses.

WVILLIAM II. A. DAVIDSON.

Witnesses:

C. S. DRURY, V. E. HoDoEs.

